Metronidazole

1 INDICATIONS AND USAGE Metronidazole gel, 1% is nitroimidazole indicated for the topical treatment of inflammatory lesions of rosacea. Metronidazole gel, 1% is a nitroimidazole indicated for the topical treatment of inflammatory lesions of rosacea. ( 1 )

2 DOSAGE AND ADMINISTRATION Cleanse treated areas before the application of metronidazole gel. Apply and rub in a thin film of metronidazole gel once daily to affected area(s). Cosmetics may be applied after the application of metronidazole gel. For topical use only, not for oral, ophthalmic, or intravaginal use. Cleanse treated areas before the application of metronidazole gel ( 2 ) Apply and rub in a thin film of metronidazole gel once daily to affected area(s). ( 2 ) Cosmetics may be applied after the application of metronidazole gel. ( 2 ) Not for oral, ophthalmic or intravaginal use. ( 2 )

5 WARNINGS AND PRECAUTIONS Neurologic Disease: Peripheral neuropathy, characterized by numbness or paresthesia of an extremity has been reported in patients treated with systemic metronidazole. Peripheral neuropathy has been reported with the post approval use of topical metronidazole. Immediate reevaluate Metronidazole gel therapy if abnormal neurologic signs appear. ( 5.1 ) Blood Dyscrasias: Metronidazole gel is a nitroimidazole; use with care in patients with evidence of, or history of, blood dyscrasia. ( 5.2 ) Contact Dermatitis: If dermatitis occurs, patients may need to discontinue use. ( 5.3 ) Eye Irritation: Topical metronidazole has been reported to cause tearing of the eyes. Avoid contact with the eyes. ( 5.4 ) 5.1 Neurologic Disease Peripheral neuropathy, characterized by numbness or paresthesia of an extremity, has been reported in patients treated with systemic metronidazole. peripheral neuropathy has been reported with the post approval use of topical metronidazole. Immediately reevaluate metronidazole gel therapy if abnormal neurologic signs appear. Administer metronidazole with caution to patients with central nervous system diseases. 5.2 Blood Dyscrasias Metronidazole gel is a nitroimidazole; use with care in patients with evidence of, or history of, blood dyscrasia. 5.3 Contact Dermatitis Irritant and allergic contact dermatitis have been reported with metronidazole gel. If dermatitis occurs, patients may need to discontinue use. 5.4 Eye Irritation Topical metronidazole has been reported to cause tearing of the eyes. Avoid contact with the eyes.

4 CONTRAINDICATIONS Metronidazole gel is contraindicated in patients with a history of hypersensitivity to metronidazole or to any other ingredient in the formulation. Metronidazole gel is contraindicated in those patients with a history of hypersensitivity to metronidazole or to any other ingredient in this formulation. ( 4 )

7 DRUG INTERACTIONS Oral metronidazole has been reported to potentiate the anticoagulant effect of coumarin and warfarin, resulting in a prolongation of prothrombin time. Use caution when prescribing for patients who are receiving anticoagulant treatment. Oral metronidazole has been reported to potentiate the anticoagulant effect of coumarin and warfarin, resulting in a prolongation of prothrombin time. Use caution when administering metronidazole gel concomitantly to patients who are receiving anticoagulant treatment. ( 7 )

8.1 Pregnancy Risk Summary Available data have not established an association between metronidazole use during pregnancy and major birth defects, miscarriage or other adverse maternal or fetal outcomes. No fetotoxicity was observed after oral administration of metronidazole in pregnant rats or mice. The available data do not allow the calculation of relevant comparisons between the systemic exposures of metronidazole observed in animal studies to the systemic exposures that would be expected in humans after topical use of metronidazole gel. The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.

8.2 Lactation Risk Summary It is not known whether metronidazole is present in human milk after topical administration. Published literature reports the presence of metronidazole in human milk after oral administration. There are no data on the effects of metronidazole on milk production. Because of the potential for serious adverse reactions, advise patients that breastfeeding is not recommended during treatment with metronidazole gel.

6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: ● Neurologic Disease [see Warnings and Precautions (5.1)] ● Contact Dermatitis [see Warnings and Precautions (5.3)] ● Eye Irritation [see Warnings and Precautions (5.4)] Most common adverse reactions (incidence > 2%) are nasopharyngitis, upper respiratory tract infection, and headache. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. In a controlled clinical trial, 557 subjects used metronidazole gel, 1% and 189 subjects used the gel vehicle once daily for up to 10 weeks. The following table summarizes selected adverse reactions that occurred at a rate of ≥1% and at a higher rate than vehicle: Table 1: Adverse Reactions That Occurred at a Rate of ≥1% and Higher Than Vehicle in Subjects Treated with metronidazole gel for Up to 10 Weeks Preferred Term Metronidazole Gel, 1% Vehicle (N= 557) N (%) (N= 189) N (%) Influenza 8 (1.4) 1 (0.5) Upper respiratory tract infection 14 (2.5) 4 (2.1) Urinary tract infection 6 (1.1) 1 (0.5) Headache 12 (2.2) 1 (0.5) Contact dermatitis 7 (1.3) 1 (0.5) Hypertension 6 (1.1) 1 (0.5) Table 2: Local Cutaneous Signs and Symptoms of Irritation That Were Worse Than Baseline in Subjects Treated with metronidazole gel for Up to 10 Weeks Metronidazole Gel, 1% Vehicle Sign/Symptom (N= 544) N (%) (N= 184) N (%) Dryness 138 (25.4) 63 (34.2) Mild 93 (17.1) 41 (22.3) Moderate 42 (7.7) 20 (10.9) Severe 3 (0.6) 2 (1.1) Scaling 134 (24.6) 60 (32.6) Mild 88 (16.2) 32 (17.4) Moderate 43 (7.9) 27 (14.7) Severe 3 (0.6) 1 (0.5) Pruritus 86 (15.8) 35 (19.0) Mild 53 (9.7) 21 (11.4) Moderate 27 (5.0) 13 (7.1) Severe 6 (1.1) 1 (0.5) Stinging/burning 56 (10.3) 28 (15.2) Mild 39 (7.2) 18 (9.8) Moderate 7 (1.3) 9 (4.9) Severe 10 (1.8) 1 (0.5) The following additional adverse reactions have been reported with the topical use of metronidazole: transient redness, metallic taste, tingling or numbness of extremities, and nausea. 6.2 Post marketing Experience The following adverse reaction has been identified during post-approval use of topical metronidazole. Because this reaction is reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate the frequency or establish a causal relationship to drug exposure. Nervous System Disorders: Peripheral neuropathy Ophthalmic Adverse Reactions: Tearing of the eyes